Thoracic ligament ossification in patients with cervical ossification of the posterior longitudinal ligaments: tandem ossification in the cervical and thoracic spine

Degenerative Thoracic Myelopathy: A Scoping Review of Epidemiology, Genetics, and Pathogenesis

STUDY DESIGN

Literature Review.

OBJECTIVE

Myelopathy affecting the thoracic spinal cord can arise secondary to several aetiologies which have similar presentation and management. Consequently, there are many uncertainties in this area, including optimal terminology and definitions. Recent collaborative cervical spinal research has led to the proposal and subsequent community adoption of the name degenerative cervical myelopathy(DCM), which has facilitated the establishment of internationally-agreed research priorities for DCM. We put forward the case for the introduction of the term degenerative thoracic myelopathy(DTM) and degenerative spinal myelopathy(DSM) as an umbrella term for both DCM and DTM.

METHODS

Following PRISMA guidelines, a systematic literature search was performed to identify degenerative thoracic myelopathy literature in Embase and MEDLINE.

RESULTS

Conditions encompassed within DTM include thoracic spondylotic myelopathy, ossification of the posterior longitudinal ligament, ossification of the ligamentum flavum, calcification of ligaments, hypertrophy of ligaments, degenerative disc disease, thoracic osteoarthritis, intervertebral disc herniation, and posterior osteophytosis. The classic presentation includes girdle pain, gait disturbance, leg weakness, sensory disturbance, and bladder or bowel dysfunction, often with associated back pain. Surgical management is typically favoured with post-surgical outcomes dependent on many factors, including the causative pathology, and presence of additional stenosis.

CONCLUSION

The clinical entities encompassed by the term DTM are interrelated, can manifest concurrently, and present similarly. Building on the consensus adoption of DCM in the cervical spine and the recent proposal of degenerative cervical radiculopathy(DCR), extending this common nomenclature framework to the terms degenerative spinal myelopathy and degenerative thoracic myelopathy will help improve recognition and communication.

Current understanding of tandem spinal stenosis: epidemiology, diagnosis, and surgical strategy

Tandem spinal stenosis (TSS) is defined as the concomitant occurrence of stenosis in at least two or more distinct regions (cervical, thoracic, or lumbar) of the spine and may present with a constellation of signs and symptoms. It has four subtypes, including cervico-lumbar, cervico-thoracic, thoraco-lumbar, and cervico-thoraco-lumbar TSS. The prevalence of TSS varies depending on the different subtypes and cohorts.

The main aetiologies of TSS are spinal degenerative changes and heterotopic ossification, and patients with developmental spinal stenosis, ligament ossification, and spinal stenosis at any region are at an increased risk of developing TSS.

The diagnosis of TSS is challenging. The clinical presentation of TSS could be complex, concealed, or severe, and these features may be confusing to clinicians, resulting in an incomplete or delayed diagnosis. Additionally, a consolidated diagnostic criterion for TSS is urgently required to improve consistency across studies and form a basis for establishing treatment guidelines.

The optimal treatment option for TSS is still under debate; areas of controversies include choice of the decompression range, choice between simultaneous or staged surgical patterns, and the order of the surgeries.

The present study reviews publications on TSS, consolidates current awareness on prevalence, aetiologies, potential risk factors, diagnostic dilemmas and criteria, and surgical strategies based on TSS subtypes. This is the first review to include thoracic spinal stenosis as a candidate disorder in TSS and aims at providing the readers with a comprehensive overview of TSS.

Distinct progression pattern of ossification of the posterior longitudinal ligament of the thoracic spine versus the cervical spine: a longitudinal whole-spine CT study

OBJECTIVE

Data regarding risk factors for the progression of ossification of the posterior longitudinal ligament (OPLL) in the thoracic spine are scarce. Therefore, in this study, the authors aimed to elucidate the difference in the radiographic progression pattern of OPLL and its risk factors between cervical and thoracic OPLL using longitudinally acquired whole-spine CT scans.

METHODS

Overall, 123 patients with symptomatic OPLL who underwent repeated whole-spine CT examinations, with an average interval of 49 months (at least 3 years) between scans, were retrospectively reviewed. Progression of OPLL was assessed to compare the distribution of OPLL over the entire spine on the initial and final CT scans. Patients were divided into a cervical OPLL (C-OPLL) group and a thoracic OPLL (T-OPLL) group according to the location of the main lesion. The progression pattern of OPLL and its risk factors were compared between the two groups using the Student t-test or Mann-Whitney U-test.

RESULTS

In the C-OPLL group, 15 (22.1%) of 68 patients had OPLL progression, of whom 12 patients (80.0%) had progression only in the cervical spine and 3 patients (20.0%) had progression in multiple regions (cervical and thoracic/lumbar). In the T-OPLL group, 16 (29.1%) of 55 patients had OPLL progression, of which 3 patients (18.8%) had progression only in the thoracic spine and 8 patients (50.0%) had progression in multiple regions. Young age was a common risk factor for OPLL progression regardless of the location of OPLL, and this trend was more pronounced in the T-OPLL group than in the C-OPLL group. High BMI, male sex, and multilevel, severe T-OPLL were identified as independent risk factors for progression of T-OPLL (OR 1.19, 95% CI 1.03-1.37; OR 10.5, 95% CI 1.39-81.94; and OR 1.24, 95% CI 1.16-1.45, respectively).

CONCLUSIONS

Patients with T-OPLL are predisposed to diffuse progression of OPLL over the entire spine, whereas patients with C-OPLL are likely to have progression in only the cervical spine. Young age and high BMI are significant risk factors for OPLL progression, especially in patients with T-OPLL. Our study highlights the need for continued follow-up in patients with T-OPLL, especially in young patients and those with obesity, for early detection of spinal cord and cauda equina symptoms due to the progression of OPLL throughout the spine.

Progression of Spinal Ligament Ossification in Patients with Thoracic Myelopathy

Objective

To evaluate the rate of increase in thickness and cross‐section area (CSA) of the ossification in thoracic myelopathy with or without cervical and lumbar spinal ligament ossification.

Methods

A total of 24 patients with 170 segments (47 ligamentum flavum [OLF] and 123 cases of ossification of the posterior longitudinal ligament [OPLL]) of spinal ligament ossification between January 2012 and March 2019 at a single institution were retrospectively reviewed. Demographic data, classification of OPLL, Sato classification of OLF, pre‐ and postoperative neurological function and complications were recorded. The thickness and CSA at the segment of maximum compression were measured with Image J software on the axial CT image.

Results

Twelve female and 12 male patients with thoracic myelopathy and spinal ligament ossification were enrolled in the study. The mean age of the patients was 54.0 ± 11.9 years with an average follow‐up of 22.2 ± 23.5 months. Overall, the mean rate of progression in thickness and CSA was 1.2 ± 1.6 and 18.4 ± 50.6 mm²/year, respectively. Being female, aging (≥45 years), and lower BMI (<28 kg/m²) predisposed patients to have faster ossification growth in thickness and CSA. The difference between the rate of OPLL and OLF progression in thickness and CSA was not significant. However, the rate of OPLL progression in the thoracic spine was significantly higher than that in the cervical spine regarding thickness (1.4 ± 1.9 vs. 0.6 ± 0.7 mm/year) and CSA (27.7 ± 72.0 vs. 7.3 ± 10.3 mm²/year).

Conclusion

This is the first study to investigate ligament ossification progression in patients with thoracic myelopathy. The difference between the rate of OPLL and OLF progression in thickness and CSA was not significant. However, the rate of thoracic OPLL progression in thickness and CSA was significantly higher than that in the cervical spine.

Should asymptomatic cervical stenosis be treated in the setting of progressive thoracic myelopathy? A systematic review of the literature

PURPOSE

Unlike tandem stenosis of the cervical and lumbar spine, tandem cervical and thoracic stenosis (TCTS) of the spine is less common, and the approach and order of intervention are controversial. We aim to review the literature to evaluate the incidence and interventions for patients with cervical and thoracic stenosis. We provide illustrative cases to demonstrate that thoracic myelopathy in the setting of asymptomatic cervical stenosis can be treated safely.

METHODS

A systematic review of the literature through electronic databases of PubMed, EMBASE, Web of Science, and Cochrane Library was performed to present the current literature that evaluates TCTS as it relates to incidence and surgical interventions. We also present two cases of patients undergoing operative intervention for thoracic myelopathy in the setting of concurrent cervical stenosis.

RESULTS

A total of 26 English original studies and case reports were identified. Nine studies evaluated the incidence of TCTS. 20 studies with a total of 168 patients with TCTS presented information on surgical intervention options. There is an overall aggregate incidence of 11.6% (530/4751) based on incidence studies. 165 patients underwent thoracic intervention. Of these patients, 63 patients underwent cervical intervention first, 29 underwent thoracic intervention first, and 73 underwent simultaneous, single-stage intervention.

CONCLUSIONS

In patients presenting with myelopathy, both cervical and thoracic spine should be evaluated for TCTS. Order of operative intervention is tailored to clinical and radiographic information. In cases of thoracic myelopathy with asymptomatic cervical stenosis, thoracic intervention can be pursued with precautions to prevent further cervical cord injury.

Thoracic ossification of the ligamentum flavum causing acute myelopathy in a patient with cervical ossification of the posterior longitudinal ligament: illustrative case

BACKGROUND

Ossification of the ligamentum flavum (OLF) has been well characterized as a distinct entity but also in tandem with ossification of the posterior longitudinal ligament (OPLL) in noncontiguous spinal regions. The majority of OLF cases are reported from East Asian countries where prevalent, but such cases are rarely reported in the North American population.

OBSERVATIONS

The authors present a case of a Thai-Cambodian American who presented with symptomatic thoracic OLF in tandem with asymptomatic cervical OPLL. A “floating” thoracic laminectomy, resection of OLF, and partial dural ossification (DO) resection with circumferential release of ossified dura were performed. Radiographic dural reexpansion and spinal cord decompression occurred despite the immediate intraoperative appearance of persistent thecal sac compression from retained DO.

LESSONS

Entire spinal axis imaging should be considered for patients with spinal ligamentous ossification disease, particularly in those of East Asian backgrounds. A floating laminectomy is one of several surgical approaches for OLF, but no consensus approach has been clearly established. High surgical complication rates are associated with thoracic OLF, most commonly dural tears/cerebrospinal fluid (CSF) leaks. DO commonly coexists with OLF, is recognizable on computed tomographic scans, and increases the risk of CSF leaks.

Clinical Comparison of Selective versus Nonselective Decompression for Symptomatic Tandem Stenosis of the Cervical and Thoracic Spine: A Retrospective Cohort Study

OBJECTIVE

The aim of the present paper was to reveal the clinical differences between selective and nonselective decompression for symptomatic tandem stenosis of the cervical and thoracic spine (TSCTS).

METHODS

A total of 34 patients were eligible and included in the study. Among them, 8 patients underwent selective cervical decompression (CD), 15 patients underwent selective thoracic decompression (TD), and 11 patients underwent combined CD and TD (CTD) surgery. Age, sex, operative time, intraoperative blood loss, postoperative hospital stay, inpatient expenditure, preoperative upper Japanese Orthopaedic Association (JOA) rate, canal occupation rate, high-intensity T2-weighted image (T2WI) of the spinal cord, and preoperative and postoperative JOA scores were compared among the three groups.

RESULTS

The CD group had shorter operative time (138.8 ± 36.1 vs 229.7 ± 95.8 vs 328.6 ± 94.8, min, P < 0.001), less intraoperative blood loss (141.3 ± 116.7 vs 496.7 ± 361.8 vs 654.6 ± 320.5, mL, P = 0.004), and shorter postoperative hospital stay (4.6 ± 1.6 vs 9.0 ± 3.5 vs 10.3 ± 6.6, days, P = 0.008), as well as lower preoperative upper JOA rate (34.1 ± 5.6 vs 53.9 ± 8.4 vs 48.2 ± 15.2, %, P = 0.001) than the TD and CTD groups. The CTD group had higher inpatient expenditure than the CD and TD groups (87,850 ± 18,379 vs 55,100 ± 12,890 vs 55,772 ± 15,715, CNY, P < 0.001). The cervical canal occupation rates were similar among different groups (P > 0.05); however, the TD group showed a higher thoracic canal occupation rate than the CD group (58.3 ± 14.7 vs 43.3 ± 12.3, %, P = 0.035). All positive levels in high-intensity T2WI of the spinal cord were decompressed. The preoperative JOA scores as well as the postoperative JOA scores at 6 months and at last follow-up were comparable among the three groups (P > 0.05). Similarly, the JOA recovery rate showed no significant difference among the groups (P > 0.05).

CONCLUSION

Selective CD or TD alone demonstrated similar clinical effectiveness to nonselective and combined CTD for TSCTS. Individualized surgical decision should be made after meticulous assessments of clinical and radiological manifestations, general patient condition, and socioeconomic factors.

Delayed Diagnosis of Tandem Spinal Stenosis: A Retrospective Institutional Review

Background

Tandem spinal stenosis (TSS) is defined as simultaneous spinal stenosis in the cervical, thoracic, and/or lumbar regions and may present with both upper and lower motor neuron symptoms, neurogenic claudication, and gait disturbance. Current literature has focused mainly on the prevalence of TSS and treatment methods, while the incidence of delayed TSS diagnosis is not well defined. The purpose of this study was to determine the incidence of delayed TSS diagnosis at our institution and describe the clinical characteristics commonly observed in their particular presentation.

Methods

Following institutional review board approval, an institutional billing database review was performed for patients who underwent a spinal decompression procedure between 2006 and 2016. Thirty-three patients who underwent decompression on 2 separate spinal regions within 1 year were included for review. Patients with delayed diagnosis of TSS following the first surgery were differentiated from those with preoperative diagnosis of TSS.

Results

TSS requiring surgical decompression occurred in 33 patients, with the incidence being 2.06% in this cohort. Fifteen patients received a delayed diagnosis after the first surgical decompression (45%) and were found to have a longer interval between decompressions (7.6 ± 2.1 months versus 4.01 ± 3 months, P = .0004). Patients undergoing lumbar decompression as the initial procedure were more likely to have a delayed diagnosis of TSS (8 versus 2 patients, P = .0200). The most common presentation of delayed TSS was pain and myelopathic symptoms that persisted after decompressive surgery.

Conclusion

TSS should remain within the differential diagnosis for patients at initial presentation of spinal stenosis. In addition, suspicion of TSS should be heightened if preoperative symptoms fail to expectedly improve following decompression even if overt myelopathic signs are not present.

Level of Evidence

4.

A Systematic Review of Classification Systems for Cervical Ossification of the Posterior Longitudinal Ligament

DESIGN

Systematic review.

OBJECTIVE

To conduct a systematic review to (1) summarize various classification systems used to describe cervical ossification of the posterior longitudinal ligament (OPLL) and (2) evaluate the diagnostic accuracy of various imaging modalities and the reliability of these classification systems.

METHODS

A search was performed to identify studies that used a classification system to categorize patients with OPLL. Furthermore, studies were included if they reported the diagnostic accuracy of various imaging modalities or the reliability of a classification system.

RESULTS

A total of 167 studies were deemed relevant. Five classification systems were developed based on X-ray: the 9-classification system (0.60%); continuous, segmental, mixed, localized or focal, circumscribed and others (92.81%); hook, staple, bridge, and total types (2.40%); distribution of OPLL (2.40%); and K-line classification (4.19%). Six methods were based on computed tomography scans: free-type, contiguous-type, and broken sign (0.60%); hill-, plateau-, square-, mushroom-, irregular-, or round-shaped (5.99%); rectangular, oval, triangular, or pedunculate (1.20%); centralized or laterally deviated (1.80%); plank-, spindle-, or rod-shaped (0.60%); and rule of nine (0.60%). Classification systems based on 3-dimensional computed tomography were bridging and nonbridging (1.20%) and flat, irregular, and localized (0.60%). A single classification system was based on magnetic resonance imaging: triangular, teardrop, or boomerang. Finally, a variation of methods was used to classify OPLL associated with the dura mater (4.19%).

CONCLUSIONS

The most common method of classification was that proposed by the Japanese Ministry of Health, Labour and Welfare. Other important methods include K-line (+/-), signs of dural ossification, and patterns of distribution.

Prevalence and Distribution of Diffuse Idiopathic Skeletal Hyperostosis on Whole-spine Computed Tomography in Patients With Cervical Ossification of the Posterior Longitudinal Ligament: A Multicenter Study

STUDY DESIGN

This was a retrospective multicenter study.

OBJECTIVE

To clarify the progression of diffuse idiopathic skeletal hyperostosis (DISH) using whole-spine computed tomography in patients with cervical ossification of the posterior longitudinal ligament (OPLL).

SUMMARY OF BACKGROUND DATA

DISH and cervical OPLL frequently coexist, and can cause ankylosing spinal fractures due to biomechanical changes and fragility of the affected vertebrae. The epidemiology and pathophysiology of DISH occurring with cervical OPLL are unclear.

MATERIALS AND METHODS

We used whole-spine computed tomography to determine the prevalence of DISH in 234 patients with a diagnosis of cervical OPLL based on plain cervical radiographs. We established a novel system for grading the progression of DISH based on a cluster analysis of the DISH distribution along the spine. We calculated the correlation coefficient between this grading system and patient age.

RESULTS

The prevalence of DISH in patients with cervical OPLL was 48.7%. Patients with DISH were significantly older than those who did not have DISH (67.3 vs. 63.4 y; P=0.005). Cluster analysis classified the DISH distribution into 6 regions, based on the levels affected: C2-C5, C3-T1, C6-T5, T3-10, T8-L2, and T12-S1. DISH was observed most frequently at T3-T10. We defined a system for grading DISH progression based on the number of regions involved, from grade 0 to 6. DISH was distributed at T3-T10 in >60% of the grade 1 patients, whereas most patients with DISH at the cervical or lumbar spine were grade 4 or 5. There was a weak but significant correlation between the DISH grade and patient age.

CONCLUSIONS

DISH was present in nearly half of the patients with cervical OPLL. DISH was more common in older patients. DISH developed at the thoracic level and progressed into the cervical and/or lumbar spine with age.

LEVEL OF EVIDENCE

Level III.

Cervical Myelopathy Secondary to Combined Ossification of Ligamentum Flavum and Posterior Longitudinal Ligament-A Case Report

In the cervical spine, the combined ossification of the ligamentum flavum (OLF) and posterior longitudinal ligament is rarely seen. Patients are usually treated with cervical laminectomy or laminoplasty with OLF resection. In most of the cases, OLF is adhered to the dura and there is a risk of dural tear or cerebrospinal fluid (CSF) leakage during its resection. In this case report, the authors present results of laminectomy with debulking instead of complete excision of OLF for spinal cord decompression in a cervical myelopathy case in which OLF was adhered to the dura. A 69-year-old man presented with insidious onset weakness in bilateral lower limbs and unsteady gait, which he had experienced 1 month. He has a history of neck pain with left upper limb radiation for the last 2 years. Magnetic resonance imaging showed C5-6 severe central canal stenosis with underlying myelomalacia. Computed tomography showed ossification posterior longitudinal ligament and OLF contributing to severe central canal stenosis at the C5-6 level. The patient underwent C4-C6 laminectomy, debulking of OLF, posterior instrumentation, and fusion with autogenous bone graft from C3 to C6. A histological specimen showed osseous tissue within the ligamentum flavum. After surgery the patient's symptoms improved and no recurrence was observed at 4 years after surgery. The symptoms of myelopathy were successfully treated with debulking instead of complete excision of OLF, thus reducing the risk of dural tear or CSF leakage.

Distribution of ossified spinal lesions in patients with severe ossification of the posterior longitudinal ligament and prediction of ossification at each segment based on the cervical OP index classification: a multicenter study (JOSL CT study)

Background

In patients with ossification of the posterior longitudinal ligament (OPLL) in the cervical spine, it is well known that the thoracic ossified lesions often coexist with the cervical lesions and can cause severe myelopathy. However, the prevalence of OPLL at each level of the thoracic and lumbar spinal segments is unknown. The aims of this study were to investigate how often OPLL occurs at each level in the thoracolumbar spine in patients with a radiological diagnosis of cervical OPLL and to identify the spinal levels most likely to develop ossification.

Methods

Data were collected from 20 institutions in Japan. Three hundred and twenty-two patients with a diagnosis of cervical OPLL were included. The OPLL index (OP index), defined as the sum of the vertebral body and intervertebral disc levels where OPLL is present, was used to determine disease severity. An OP index ≥20 was defined as severe OPLL. The prevalence of OPLL at each level of the thoracic and lumbar spinal segments was calculated.

Results

Women were more likely to have ossified lesions in the thoracolumbar spine than men. Severe OPLL was significantly more common in women than in men (20% vs. 4.5%). For thoracic vertebral OPLL, the most frequently affected was the T1 segment in both men and women, followed by the T1/2 and T3/4 intervertebral levels in men and women, respectively. Ossified lesions were frequently seen at the intervertebral and vertebral levels around the cervicothoracic and thoracolumbar junctions in men with severe OPLL, whereas OPLL was more diffusely distributed in the thoracic spine in women with severe OPLL.

Conclusion

Thoracolumbar OPLL occurred most often at T1 in men and at T3/4 in women. In severe OPLL cases, although ossified lesions were frequently seen at the intervertebral and vertebral levels around the cervicothoracic and thoracolumbar junctions in men, OPLL could be observed more diffusely in the thoracic spine in women.

Magnetic resonance imaging assessment of degenerative cervical myelopathy: a review of structural changes and measurement techniques

Degenerative cervical myelopathy encompasses a spectrum of age-related structural changes of the cervical spine that result in static and dynamic injury to the spinal cord and collectively represent the most common cause of myelopathy in adults. Although cervical myelopathy is determined clinically, the diagnosis requires confirmation via imaging, and MRI is the preferred modality. Because of the heterogeneity of the condition and evolution of MRI technology, multiple techniques have been developed over the years in an attempt to quantify the degree of baseline severity and potential for neurological recovery. In this review, these techniques are categorized anatomically into those that focus on bone, ligaments, discs, and the spinal cord. In addition, measurements for the cervical spine canal size and sagittal alignment are also described briefly. These tools have resulted collectively in the identification of numerous useful parameters. However, the development of multiple techniques for assessing the same feature, such as cord compression, has also resulted in a number of challenges, including introducing ambiguity in terms of which methods to use and hindering effective comparisons of analysis in the literature. In addition, newer techniques that use advanced MRI are emerging and providing exciting new tools for assessing the spinal cord in patients with degenerative cervical myelopathy.

Prevalence and distribution of ossification of the supra/interspinous ligaments in symptomatic patients with cervical ossification of the posterior longitudinal ligament of the spine: a CT-based multicenter cross-sectional study

Background

Supra/interspinous ligaments connect adjacent spinous processes and act as a stabilizer of the spine. As with other spinal ligaments, it can become ossified. However, few report have discussed ossification supra/interspinous ligaments (OSIL), so its epidemiology remains unknown. We therefore aimed to investigate the prevalence and distribution of OSIL in symptomatic patients with cervical ossification of the posterior longitudinal ligament (OPLL).

Methods

The participants of our study were symptomatic patients with cervical OPLL who were diagnosed by standard radiographs of the cervical spine. The whole spine CT data as well as clinical parameters such as age and sex were obtained from 20 institutions belong to the Japanese Multicenter Research Organization for Ossification of the Spinal Ligament (JOSL). The prevalence and distribution of OSIL and the association between OSIL and clinical parameters were reviewed. The sum of the levels involved by OPLL (OP-index) and OSIL (OSI-index) as well as the prevalence of ossification of the nuchal ligament (ONL) were also investigated.

Results

A total of 234 patients with a mean age of 65 years was recruited. The CT-based evidence of OSIL was noted in 68 (54 males and 14 females) patients (29%). The distribution of OSIL showed a significant thoracic preponderance. In OSIL-positive patients, single-level involvement was noted in 19 cases (28%), whereas 49 cases (72%) presented multi-level involvement. We found a significant positive correlation between the OP-index grade and OSI-index. ONL was noted at a significantly higher rate in OSIL-positive patients compared to negative patients.

Conclusions

The prevalence of OSIL in symptomatic patients with cervical OPLL was 29%. The distribution of OSIL showed a significant thoracic preponderance.

One-staged combined decompression for the patients with cervico-thoracic tandem spinal stenosis

PURPOSE

To report the techniques and safety of one-staged combined decompression for the patients with tandem spinal stenosis (TSS) at cervical and thoracic spine.

METHODS

Sixteen TSS subjects, who received combined decompression from Aug 2005 to Feb 2012, were reviewed. The essentials of our surgical strategy included: choosing patients with TSS from cervical to upper or middle thoracic spine, using one single posterior incision, simplifying surgical maneuvers and performing circumferential decompression for thoracic compression if it was indicated. The Japanese Orthopedic Association (JOA) scale for cervical myelopathy was employed to evaluate the neurological status, and Hirabayashi's system to assess neurological recovery rate.

RESULTS

The average operation duration, blood loss and postoperative hospitalization were 242.8 ± 89.9 min, 1581.3 ± 1237.2 ml and 11.9 ± 7.5 days, respectively. Six subjects (37.5 %) suffered instant neurological deterioration. Other complications included cerebrospinal fluid leakage (10 subjects, 62.5 %), new radiculopathy (two subjects), urinary infection, lung infection and pulmonary thromboembolism. Four subjects received extra-thoracic decompression due to the remaining anterior compression in one subject and new emerging compression in other three subjects. Eventually, mean JOA score was elevated from 9.8 ± 2.1 to 13.7 ± 2.7 after this procedure, and the neurological recovery of seven subjects was rated as excellent, four as good, two as fair, three as unchanged or deteriorated. The overall recovery rate was 53.7 %.

CONCLUSION

Combined cervico-thoracic decompression could provide fair neurological outcomes for patients with cervico-thoracic TSS, but it was complicated with high rate of undesirable postoperative events. So, more efforts should be done against its eventful postoperative course before its wide application.

Asymptomatic Stenosis in the Cervical and Thoracic Spines of Patients with Symptomatic Lumbar Stenosis

Study Design Retrospective study. Objective Studies on age-related degenerative changes causing concurrent stenoses in the cervical, thoracic, and lumbar spines (triple stenosis) are rare in the literature. Our objectives were to determine: (1) the incidence of asymptomatic radiologic cervical and thoracic stenosis in elderly patients with symptomatic lumbar stenosis, (2) the incidence of concurrent radiologic spinal stenosis in the cervical and thoracic spines, and (3) the radiologic features of cervical stenosis that might predict concurrent thoracic stenosis. Methods Whole-spine T2 sagittal magnetic resonance images of patients older than 80 and diagnosed with lumbar spinal stenosis between January 2003 and January 2012 were evaluated retrospectively. We included patients with asymptomatic spondylotic cervical and thoracic stenosis. We measured the anteroposterior diameters of the vertebral body, bony spinal canal, and spinal cord, along with the Pavlov ratio and anterior or posterior epidural stenosis at the level of the disk for each cervical and thoracic level. We compared the radiologic parameters between the subgroups of cervical stenosis with and without thoracic stenosis. Results Among the 460 patients with lumbar stenosis, 110 (23.9%) had concurrent radiologic cervical stenosis and 112 (24.3%) had concurrent radiologic thoracic stenosis. Fifty-six patients (12.1%) had combined radiologic cervical and thoracic stenosis in addition to their symptomatic lumbar stenosis (triple stenosis). Anterior epidural stenosis at C7-T1 was associated with a high prevalence of thoracic stenosis. Conclusions It appears that asymptomatic radiologic cervical and thoracic stenosis is common in elderly patients with symptomatic lumbar stenosis.

Prevalence, Distribution, and Significance of Incidental Thoracic Ossification of the Ligamentum Flavum in Korean Patients with Back or Leg Pain : MR-Based Cross Sectional Study

OBJECTIVE

Thoracic ossification of the ligamentum flavum (OLF) is a relatively rare disease. Because of ambiguous clinical symptom, it is difficult for early diagnosis of OLF and subsequent treatment can be delayed or missed. Therefore, the purpose of this study is to comprehensively assess the prevalence and distribution of thoracic OLF by magnetic resonance imaging (MRI) and coexisting spinal disease in Korean patients with back pain or leg pain.

METHODS

The sample included 2134 Korean patients who underwent MRI evaluation for back pain. The prevalence and distribution of thoracic OLF were assessed using lumbar MRI with whole spine sagittal images. Additionally, we examined the presence of coexisting lumbar and cervical diseases. The presence of thoracic OLF as well as clinical parameters such as age, sex, and surgery were retrospectively reviewed.

RESULTS

The prevalence of thoracic OLF in total patients was 16.9% (360/2134). The prevalence tended to increase with aging and was higher in women than in men. The lower thoracic segment of T10-11 was the most frequently affected segment. Of the 360 patients with OLF, 31.9% had coexisting herniated thoracic discs at the same level. Approximately 74% of the patients with OLF had coexisting lumbar and cervical disease. Nine (2.5%) of 360 OLF patients underwent surgery for thoracic lesion.

CONCLUSION

The prevalenceof thoracic OLF was relatively higher than those of previous reports. And coexisting lumbar and cervical disease were very frequent. Therefore, we should check coexisting spinal diseases and the exact diagnostic localization of ossification besides lumbar disease.

Degenerative Cervical Myelopathy: Epidemiology, Genetics, and Pathogenesis

STUDY DESIGN

Review.

OBJECTIVE

To formally introduce "degenerative cervical myelopathy" (DCM) as the overarching term to describe the various degenerative conditions of the cervical spine that cause myelopathy. Herein, the epidemiology, pathogenesis, and genetics of conditions falling under this hypernym are carefully described.

SUMMARY OF BACKGROUND DATA

Nontraumatic, degenerative forms of cervical myelopathy represent the commonest cause of spinal cord impairment in adults and include cervical spondylotic myelopathy, ossification of the posterior longitudinal ligament, ossification of the ligamentum flavum, and degenerative disc disease. Unfortunately, there is neither a specific term nor a specific diagnostic International Classification of Diseases, Tenth Revision code to describe this collection of clinical entities. This has resulted in the inconsistent use of diagnostic terms when referring to patients with myelopathy due to degenerative disease of the cervical spine.

METHODS

Narrative review.

RESULTS

The incidence and prevalence of myelopathy due to degeneration of the spine are estimated at a minimum of 41 and 605 per million in North America, respectively. Incidence of cervical spondylotic myelopathy-related hospitalizations has been estimated at 4.04/100,000 person-years, and surgical rates seem to be rising. Pathophysiologically, myelopathy results from static compression, spinal malalignment leading to altered cord tension and vascular supply, and dynamic injury mechanisms. Occupational hazards, including transportation of goods by weight bearing on top of the head, and other risk factors may accelerate DCM development. Potential genetic factors include those related to MMP-2 and collagen IX for degenerative disc disease, and collagen VI and XI for ossification of the posterior longitudinal ligament. In addition, congenital anomalies including spinal stenosis, Down syndrome, and Klippel-Feil syndrome may predispose to the development of DCM.

CONCLUSION

Although DCMs can present as separate diagnostic entities, they are highly interrelated, frequently manifest concomitantly, present similarly from a clinical standpoint, and seem to be in part a response to compensate and improve stability due to progressive age and wear of the cervical spine. The use of the term "degenerative cervical myelopathy" is advocated.

LEVEL OF EVIDENCE

5.

Extensive ossification of the ligamentum flavum treated with triple stage decompression: a case report

BACKGROUND CONTEXT

Concurrent ossification of the ligamentum flavum (OLF) in the cervical, thoracic, and lumbar spine is a rare occurrence often associated with rheumatologic abnormalities. Although the pathology may be asymptomatic and discovered incidentally on routine imaging, compression of the cord and surrounding nerve roots can produce myelopathic or radiculopathic symptoms that are best treated with surgical decompression. There is limited evidence to support the use of single versus multistage decompression for tandem ossification at multiple levels, although several factors including duration of symptoms have been associated with a worse prognosis.

PURPOSE

To describe the presence of extensive symptomatic tandem OLF with concurrent ossification of the posterior longitudinal ligament (PLL) and its treatment using multistage decompression.

STUDY DESIGN

Case report and literature review.

METHODS

The authors describe a case of a 35-year-old woman with OLF extending from the cervical to lumbar spine and tandem ossification of the cervical PLL. Her initial presentation was significant for symptoms consistent with thoracic myelopathy in the absence of radiculopathic findings, and initial imaging also demonstrated disc herniation at L4-L5 and L5-S1.

RESULTS

The patient was first treated with a thoracic laminectomy and fusion from T7 to T11, given her back pain and thoracic myelopathy. Persistence of myelopathic symptoms necessitated further surgical intervention with a posterior cervical decompression and fusion from C3 to T1. Finally, after the appearance of radiculopathic findings, she underwent a microscopic L4-L5 laminectomy with improvements in her symptoms and ambulation.

CONCLUSIONS

Symptomatic OLF in non-East Asian population is a rare occurrence. Its etiology is likely multifactorial, involving both biomechanical and genetic factors. Although early detection and management are necessary, multistage decompression can be an effective intervention for extensive multilevel ossification.

Ossification of the posterior longitudinal ligament in not only the cervical spine, but also other spinal regions: analysis using multidetector computed tomography of the whole spine

STUDY DESIGN

A prospective cohort study.

OBJECTIVE

To evaluate ossification of the posterior longitudinal ligament (OPLL) of the whole spine in patients with cervical OPLL and to analyze which types of cervical OPLL were associated with the other lesions in the thoracic and/or lumbar spine.

SUMMARY OF BACKGROUND DATA

OPLL is most frequently seen in the cervical spine. The coexisting ossified lesions are sometimes observed in other spinal regions. However, coexisting OPLL in other spinal regions have not yet been precisely evaluated in patients with cervical OPLL.

METHODS

One hundred seventy-eight patients with a diagnosis of cervical OPLL whose plain radiographs were obtained were included. Computed tomographic images of the whole spine were obtained. The ossification index (OS index) was newly determined according to the sum of the levels of vertebral bodies and intervertebral discs with OPLL. The patients were divided into 2 groups, the group that had OPLL only in the cervical spine (C group) and the group that had OPLL in multilevel spinal regions other than the cervical spine (M group).

RESULTS

Ninety-five (53.4%) had OPLL not only in the cervical spine, but also in other spinal regions. The M group had more females than the C group. The incidence of bridge formation in the cervical spine was higher in M group than in C group. More females had a high OS index. A positive correlation was found between the OS index of the cervical spine and the OS index of the thoracic and lumbar spine; however, the r value was small.

CONCLUSION

This study demonstrated that more than half of the patients with cervical OPLL had coexisting OPLL in the thoracic and/or lumbar spine. We strongly recommend computed tomographic analysis of the whole spine for patients with radiographical evidence of OPLL in the cervical spine for the early detection of additional sites of ossification.

Clinical features and surgical outcomes of patients with thoracic myelopathy caused by multilevel ossification of the ligamentum flavum

BACKGROUND CONTEXT

Thoracic myelopathy caused by multilevel (three or more levels) ossification of the ligamentum flavum (OLF) is rare. Little is known about its clinical features, and the surgical outcomes along with its related factors are also unclear.

PURPOSE

To describe the clinical features, assess the safety and effectiveness of surgical decompression, and determine the prognostic factors relevant for patients with thoracic myelopathy caused by multilevel OLF.

STUDY DESIGN/SETTING

A retrospective clinical study.

PATIENT SAMPLE

Seventy-five consecutive multilevel OLF patients who underwent surgical decompression were analyzed.

OUTCOME MEASURES

Modified Japanese Orthopedic Association (JOA) scale and the recovery rate.

METHODS

Patients who underwent surgical decompression for symptomatic multilevel OLF during January 1996 to June 2010 were all included. Clinical data were collected from medical and operative records; patients were evaluated by using the JOA scale preoperatively and during the follow-up. Correlations between the surgical outcome and various factors were also analyzed.

RESULTS

Forty-three men and 32 women with a mean age of 54.7 years (range 36-78 years) were included. The mean number of involved levels is 4.6 and contiguous OLF presented in 73.3% of these patients. The most common involved levels were T10/T11 (15.4%), T9/T10 (13.3%), and T11/T12 (12.5%). Coexisting spinal disorders were found in 41 patients (54.7%). Preoperative evaluation showed the mean JOA score was 5.8±1.7; 37.3% of these patients had mild myelopathy, 53.3% had moderate myelopathy, and 9.3% had severe myelopathy. All patients received posterior laminectomy. The JOA score (mean 8.2±2.1) significantly increased postoperatively (p<.05), and multiple regression analysis showed that preoperative duration of symptoms and preoperative JOA score were important predictors of surgical outcome.

CONCLUSIONS

Laminectomy with partially internal fixation is safe and effective in treatment of patients with symptomatic multilevel OLF. The results of our study show that preoperative JOA score and preoperative duration of symptoms were important predictors for the clinical outcome.

Variables affecting postsurgical prognosis of thoracic myelopathy caused by ossification of the ligamentum flavum

BACKGROUND CONTEXT

Ossification of the ligamentum flavum (OLF) may result in thoracic myelopathy (TM) because of narrowing of the spinal canal. Because symptoms vary and are subjective, diagnosis of TM caused by OLF is sometimes difficult when based on symptoms and physical examination. Posterior decompression is indicated in patients with TM caused by OLF because it is believed that surgery is the most effective treatment. However, surgical outcomes vary. We are unaware of reports of objective presurgical diagnostic parameters, such as neurologic and radiologic findings, relating to the postsurgical prognosis in patients with TM caused by OLF.

PURPOSE

To determine which presurgical and surgical variables were most closely related to postsurgical prognosis of TM caused by OLF.

STUDY DESIGN

Retrospective review of the records of the cohort of patients who had undergone surgery from 1988 through 2008 at the University of Toyama Hospital for TM caused by OLF.

PATIENT SAMPLE

Forty-one patients who had surgery for TM caused by OLF that was progressive, severe, or both and for which the diagnosis was based on clinical, radiologic, and pathologic evaluations.

OUTCOME MEASURES

Relationship between the highest follow-up Japanese Orthopaedic Association (JOA) score for neurologic evaluation and of Hirabayashi's formula to indicate the extent of normalization after surgery with respect to the following 10 variables: age at surgery; sex; duration of presurgical symptoms; complications of diabetes mellitus; complications of hypertension; presence of presurgical hyperreflexia in either or both of the patellar tendon reflex and the Achilles tendon reflex; presurgical impairment of joint position sense in the big toes; number of levels affected by OLF; concurrent spinal lesions including ossification of the posterior longitudinal ligament; and intramedullary change of the spinal cord seen on magnetic resonance imaging (MRI).

METHODS

Multiple linear analyses were used to evaluate the variables related to postsurgical recovery.

RESULTS

Presurgical impairment of joint position sense in the big toe was the most important predictor of the highest postsurgical JOA score and of the highest percentage recovery rate. The number of affected OLF levels also predicted the postsurgical highest JOA score, but not statistically significantly so. Age at surgery, sex, and duration of symptoms presurgically did not affect postsurgical recovery. Complications of diabetes mellitus or of hypertension did not affect percentage recovery rate. The difference between recovery rate in patients with or without concurrent spinal lesions was not significant. Presurgical hyperreflexia was not correlated with recovery. Postsurgical JOA scores and percentage recovery rates of scores in patients whose presurgical MRIs had shown intramedullary signal change were not statistically significantly different from those whose MRIs had not shown signal change.

CONCLUSIONS

An excellent postoperative prognosis is not always possible in patients with TM caused by OLF. It may be important to check for impairment of joint position sense in the big toe, the number of levels affected by OLF, and presurgical intramedullary signal change on MRI before continuing to surgery.

Single-stage combined decompression for patients with tandem ossification in the cervical and thoracic spine

STUDY DESIGN

Retrospective study of clinical outcomes of single-staged combined cervical and thoracic decompression for patients with tandem ossification (TO).

OBJECTIVE

To describe primary clinical outcomes of this procedure. TO is introduced to described a double ossification lesion of the posterior longitudinal ligament (OPLL) or the ligament flavum (OLF) at the cervical, thoracic and lumbar spine. In clinical practice, cervical OPLL combined with thoracic OPLL or/and OLF are the most common types of TO. However, little is known about the clinical outcomes of surgical treatment and there is no consensus on the optimal treatment to this combined disorder.

METHODS

Between January 2005 and December 2008, 15 patients of this complicated phenomenon were treated by single-staged combined cervical and thoracic decompression in conditions where patients' general condition allowed and individuals agreed on. Surgical intervention, perioperative complications, and clinical outcomes were reviewed in these 15 TO patients who were followed up for more than 2 years (range 2-5 years). Clinical symptoms were evaluated using the JOA scoring system and activity of daily life was evaluated by Nurick classification before surgery, at 6 months postoperatively, and at final follow-up. Patient satisfaction was determined at final follow-up.

RESULTS

The mean blood loss was 1,553.3 ± 735.7 ml (range 700-2,900 ml) and the mean operation time was 280.7 ± 53.6 min (range 220-370 min). The important intraoperative and postoperative complications recorded in medical documents included CSF leakage, hematoma, C5 palsy and neurological deterioration. The JOA score was significantly higher 6 months after surgery (8.1 ± 1.8 points vs. 11.0 ± 1.6 points, p < 0.0001), and there was no significant change between 6 months after surgery and final follow-up (11.0 ± 1.6 points vs. 11.3 ± 2.1, p = 0.5894). The mean Nurick classification significantly improved from grade 3.6 ± 0.7 before surgery to grade 2.5 ± 0.9 at 6 months after surgery (p < 0.001), and well maintained as grade 2.3 ± 1.0 at final follow-up (p = 0.3343). Three patients had satisfaction scores of 3 points, 5 had scores of 2 or 1 point, and 2 had score of 0 point. Pearson correlation analysis showed a significant positive correlation between satisfaction score and JOA score (r = 0.6493, p = 0.0093), and a significant negative correlation between satisfaction score and Nurick classification (r = -0.5941, p = 0.0195). Besides, perioperative complications and progression of tandem ossification which needed revision surgery had significant adverse effect on patients' satisfaction.

CONCLUSIONS

The results showed that single-staged combined decompression could provide comparable clinical outcomes, and patients' satisfaction was significantly related with postoperative neurological function. In addition, satisfaction score could be decreased by perioperative complications and progression of tandem ossification. Thus, this aggressive surgical strategy should be used more carefully with emphasis on preoperative communication with patients.

Ossification of the posterior longitudinal ligament: pathogenesis, management, and current surgical approaches. A review

Ossification of the posterior longitudinal ligament (OPLL) is an important cause of cervical myelopathy that results from bony ossification of the cervical or thoracic posterior longitudinal ligament (PLL). It has been estimated that nearly 25% of patients with cervical myelopathy will have features of OPLL. Patients commonly present in their mid-40s or 50s with clinical evidence of myelopathy. On MR and CT imaging, this can be seen as areas of ossification that commonly coalesce behind the cervical vertebral bodies, leading to direct ventral compression of the cord. While MR imaging will commonly demonstrate associated changes in the soft tissue, CT scanning will better define areas of ossification. This can also provide the clinician with evidence of possible dural ossification. The surgical management of OPLL remains a challenge to spine surgeons. Surgical alternatives include anterior, posterior, or circumferential decompression and/or stabilization. Anterior cervical stabilization options include cervical corpectomy or multilevel anterior cervical corpectomy and fusion, while posterior stabilization approaches include instrumented or noninstrumented fusion or laminoplasty. Each of these approaches has distinct advantages and disadvantages. While anterior approaches may provide more direct decompression and best improve myelopathy scores, there is soft-tissue morbidity associated with the anterior approach. Posterior approaches, including laminectomy and fusion and laminoplasty, may be well tolerated in older patients. However, there often is associated axial neck pain and less improvement in myelopathy scores. In this review, the authors discuss the epidemiology, imaging findings, and clinical presentation of OPLL. The authors additionally discuss the merits of the different surgical techniques in the management of this challenging disease.

Ossification of the posterior longitudinal ligament: a review

Ossification of the posterior longitudinal ligament (OPLL) is most commonly found in men, the elderly, and Asian patients. There are many diseases associated with OPLL, such as diffuse idiopathic skeletal hyperostosis, ankylosing spondylitis, and other spondyloarthropathies. Several factors have been reported to be associated with OPLL formation and progression, including genetic, hormonal, environmental, and lifestyle factors. However, the pathogenesis of OPLL is still unclear. Most symptomatic patients with OPLL present with neurological deficits such as myelopathy, radiculopathy, and/or bowel and bladder symptoms. There are some reports of asymptomatic OPLL. Both static and dynamic factors are related to the development of myelopathy. Plain radiography, CT, and MR imaging are used to evaluate OPLL extension and the area of spinal cord compression. Management of OPLL continues to be controversial. Each surgical technique has some advantages and disadvantages, and the choice of operation should be made case by case, depending on the patient's condition, level of pathology, type of OPLL, and the surgeon's experience. In this paper, the authors attempt to review the incidence, pathology, pathogenesis, natural history, clinical presentation, classification, radiological evaluation, and management of OPLL.

Management of ossification of the posterior longitudinal ligament of the thoracic spine

The management of thoracic ossification of the posterior longitudinal ligament has been studied by many spinal surgeons. Indications for operative intervention include progressive radiculopathy, myelopathy, and neurological deterioration. The ideal surgery for decompression remains highly debatable as various methods of surgical treatment of ossification of the posterior longitudinal ligament have been devised. Although numerous modifications to the 3 main approaches have been identified (anterior, posterior, or lateral), the indication for each depends on the nature of compression, the morphology of the lesion, the level of the compression, the structural alignment of the spine, and the neurological status of the patient. The authors discuss treatment techniques for thoracic ossification of the posterior longitudinal ligament, cite case examples from a single institution, and review the literature.

Ossification of the ligamentum flavum of the thoracic spine in the Korean population

OBJECT

Thoracic ossification of the ligamentum flavum (OLF), a main cause of thoracic myelopathy, is an uncommon disease entity. It is seen mostly in East Asia, although the majority of reports have issued from Japan. In the present study, the clinical features and prognostic factors of thoracic OLF were examined in a large number of Korean patients.

METHODS

Data from 51 consecutive patients who underwent decompressive laminectomy with or without fusion for thoracic OLF between 1998 and 2008 were retrospectively analyzed. Patients were evaluated pre- and postoperatively using the modified Japanese Orthopedic Association (JOA) scale (maximum total score of 11). Patient age, sex, preoperative symptoms, duration of initial symptoms, number of involved segments, duration of follow-up, presence of dural adhesion (dural tearing), intramedullary high signal intensity, morphological classification of OLF (axial or sagittal), coexisting disease, and fusion or no fusion were also evaluated. Surgical outcomes were assessed using JOA recovery rate/outcome scores, and patient satisfaction grades and prognostic factors were analyzed.

RESULTS

There were 18 men and 33 women with a mean age of 60.9 years (range 38-80 years). A mean preoperative JOA score of 5.5 improved to a mean score of 7.4 at the last follow-up (mean 52 months after surgery). The mean duration of the initial symptoms was 34.5 months (range 0.1-240 months) prior to surgery. The most common symptoms were motor dysfunction (80%); sensory deficit (67%); and pain, numbness, and claudication (59%) in the lower extremities. Knee hyperreflexia appeared in 69% of the patients. There were a total of 130 ossified segments, and the mean number of segments per patient was 2.6. Ninety-two (71%) of 130 segments were located below T-8. Recovery outcomes were good (18 patients), fair (16 patients), unchanged (11 patients), or worse (6 patients). Thirty-one patients (61%) were satisfied with their operations. Patients with a beak type of OLF on sagittal MR images experienced a higher recovery rate and a better satisfaction grade than did those with a round OLF. The patients with higher preoperative JOA scores demonstrated significantly higher JOA scores postoperatively (p < 0.001), and the preoperative JOA score had a significant correlation with the recovery rate in patients exhibiting mainly motor dysfunction (p = 0.040, r = 0.330).

CONCLUSIONS

Of the thoracic OLF studies published to date, the present analysis involves the largest Korean population. The most common symptoms of thoracic OLF were motor dysfunction and sensory deficit in the lower extremities, although pain, numbness, and claudication were observed in some patients and were notably accompanied by knee hyperreflexia. At a minimum of 2 years after surgery for thoracic OLF, operative outcomes were generally good, and the prognostic factors affecting good surgical outcomes included a beak type of OLF and a preoperative JOA score > 6.

Clinical analysis of thoracic ossified ligamentum flavum without ventral compressive lesion

The aim of this study was to analyze the clinical characteristics of thoracic ossified ligamentum flavum (OLF) and to elucidate prognostic factors as well as effective surgical treatment modality. The authors analyzed 106 thoracic OLF cases retrospectively from January 1999 to December 2008. The operative (n = 40) and the non-operative group (n = 66) were diagnosed by magnetic resonance imaging (MRI) and/or computed tomography (CT) imaging. We excluded cases exhibiting ventral compressive lesions causing subarachnoid space effacement in thoracic vertebrae as well as those with a coexisting cervical compressive myelopathy. Those in the operative group were treated with decompressive laminectomy as well as resection of OLF. The preoperative neurologic status and postoperative outcomes of patients, as indicated by their modified Japanese Orthopedic Association (mJOA) scores and recovery rate (RR), Modic changes, the axial (fused or non-fused) and sagittal (omega or beak) configurations of OLF, and the ratios of the cross-sectional area (CSA) and anteroposterior diameter (APD) of the most compressed level were studied. The most commonly affected segment was the T10-11 vertebral body level (n = 49, 27.1%) and the least affected segment was the T7-8 level (n = 1, 0.6%). The ratios of the CSA in non-fused and fused types were 77.3 and 59.3% (p < 0.001). When Modic changes were present with OLF, initial mJOA score was found to be significantly lower than those without Modic change (7.62 vs. 9.09, p = 0.033). Neurological status improved after decompressive laminectomy without fusion (preoperative vs. last mJOA; 7.1 ± 2.01 vs. 8.57 ± 1.91, p < 0.001). However, one patient exhibited transient deterioration of her neurological status after surgery. In the axial configuration, fused-type OLF revealed a significant risk for a decreased postoperative mJOA score (0-7, severe and moderate) (Odds ratio: 5.54, χ (2) = 4.41, p = 0.036, 95% CI: 1.014-30.256). The results indicated that the new categorization of axial-type of OLF is a helpful predictor of postoperative patient outcome and fused type was related with poor prognosis. In OLF cases free from ventral lesions compressing the spinal cord, decompressive laminectomy is enough for successful surgical outcome. Therefore, early surgical treatment will be considered in cases with fused-type OLF compressing spinal cord even though they do not have myelopathic symptoms.

Posterior decompression with kyphosis correction for thoracic myelopathy due to ossification of the ligamentum flavum and ossification of the posterior longitudinal ligament at the same level

Object

The object of this study was to evaluate the efficacy and safety of posterior decompression with kyphosis correction for thoracic myelopathy due to ossification of the ligamentum flavum (OLF) and ossification of the posterior longitudinal ligament (OPLL) at the same level.

Methods

Between January 2003 and December 2005, 11 patients (8 men and 3 women) with thoracic myelopathy due to OLF and OPLL at the same level underwent posterior decompressive laminectomy and excision of OLF. Posterior instrumentation was also performed for stabilization of the spine and reducing the thoracic kyphosis angle by approximately 5–15° (kyphosis correction), and spinal fusion was performed in all cases. The follow-up period ranged from 2 to 4 years (mean 2.8 years). The outcomes were evaluated using a recovery scale based on the Japanese Orthopaedic Association classification. The score of each patient was calculated before surgery, 1 year after surgery, and at the final follow-up visit.

Results

After surgery, the thoracic kyphosis in the stabilization area was reduced from 30.0 ± 4.02° to 20.8 ± 2.14° on average. The mean score on the Japanese Orthopaedic Association scale improved from 3.5 ± 1.69 preoperatively to 8.5 ± 1.63 at the final follow-up, with a recovery rate of 68.0%. The results were good in 9 patients and fair in 2 patients. Postoperative MR imaging showed that the spinal cord was shifted posteriorly and decompressed completely in all cases. Myelopathy was not aggravated in any case after surgery.

Conclusions

A considerable degree of neurological recovery was observed after posterior decompression and kyphosis correction. The procedure is easy to perform with a low risk of postoperative paralysis. The authors therefore suggest that the procedure is useful for patients whose spinal cords are severely impinged by OLF and OPLL at the same level.

Types and prevalence of coexisting spine lesions on whole spine sagittal MR images in surgical degenerative spinal diseases

PURPOSE

We investigated types and prevalence of coexisting lesions found on whole spine sagittal T2-weighted images (WSST2I) acquired from magnetic resonance imaging (MRI) and evaluated their clinical significance in surgical degenerative spinal diseases.

MATERIALS AND METHODS

Coexisting spinal lesions were investigated using WSST2I from 306 consecutive patients with surgical degenerative spinal diseases. Severity of coexisting lesions was classified into four grades (0-3). Lesions of grade 2 and 3 were defined as "meaningful coexisting spine lesions" (MCSL). Degenerative spinal diseases were classified into three pathologies: simple disc herniation, degenerative spinal stenosis, and ligament ossification disease. The relationships between MCSL, gender, age, and primary spine lesions were analyzed.

RESULTS

MCSL were found in 95 patients: a prevalence of 31.1%. Five out of 95 MCSL were surgically managed. The most common types of MCSL were disc herniation with 13.1% prevalence, followed by degenerative stenosis (9.5%) and ligament ossification diseases (6.8%). Older patients (age >or= 40) showed a significantly higher prevalence of MCSL than younger patients. There was no significant difference between male and female patients. The prevalence of MCSL was significantly higher (52.4%) in ligament ossification diseases than in disc herniation or spinal stenosis.

CONCLUSION

Degenerative spinal diseases showed a high prevalence of MCSL, especially in old ages and ligament ossification diseases. WSST2I is useful for diagnosing coexisting spinal diseases and to avoid missing a significant cord-compressing lesion.

Late Occurrence of Cervicothoracic Ossification of Posterior Longitudinal Ligaments in a Surgically Treated Thoracic OPLL Patient

Ossification of the posterior longitudinal ligament (OPLL) in the thoracic spine is rare, even in the Far East. A 45-year-old female presented with a 4-month history of progressive motor weakness in the lower extremities, numbness below the midthoracic area, and spastic gait disturbance. Neuroradiological examinations revealed massive OPLLs at the T4-T6 levels with severe anterior compression of the spinal cord. Anterior decompressive corpectomies with bone grafts were performed from T4 to T6 using a trans-thoracic approach. After surgery, the patient made an uneventful recovery. However, eleven years after surgery, the patient developed recurrent lower extremity weakness and spastic gait disturbance. De novo OPLLs at the C6-T2 levels were responsible for the severe spinal cord compression on this occasion. After second surgery, paralysis in both legs was resolved. We present a rare case of late cervicothoracic OPLL in a patient surgically treated for thoracic OPLL.